feat(JQLite): ready() now supports document.readyState=='complete'

JQLite.ready() used for automatic bootstrapping (when jQuery is not present)
now checks if document already is ready when first called. This simplifies
bootstrapping when the angular script is loaded asynchronously.

However if other scripts with angular app code are being loaded as well
it is developers responsibility to ensure that these scripts are loaded
after angular-loader.js is evaluated and before angular.js script is
evaluated.

docs/content/guide/bootstrap.ngdoc

@@ -48,11 +48,10 @@ initialization.
 
 # Automatic Initialization
 
-Angular initializes automatically upon `DOMContentLoaded` event, at which point Angular looks for
-the {@link api/ng.directive:ngApp `ng-app`} directive which
-designates your application root. If the {@link
-api/ng.directive:ngApp `ng-app`} directive is found then Angular
-will:
+Angular initializes automatically upon `DOMContentLoaded` event or when the `angular.js` script is
+evaluated if at that time `document.readyState` is set to `'complete'`. At this point Angular looks
+for the {@link api/ng.directive:ngApp `ng-app`} directive which designates your application root.
+If the {@link api/ng.directive:ngApp `ng-app`} directive is found then Angular will:
 
   * load the {@link guide/module module} associated with the directive.
   * create the application {@link api/AUTO.$injector injector}

src/jqLite.js

@@ -327,9 +327,14 @@ var JQLitePrototype = JQLite.prototype = {
       fn();
     }
 
-    this.bind('DOMContentLoaded', trigger); // works for modern browsers and IE9
-    // we can not use jqLite since we are not done loading and jQuery could be loaded later.
-    JQLite(window).bind('load', trigger); // fallback to window.onload for others
+    // check if document already is loaded
+    if (document.readyState === 'complete'){
+      setTimeout(trigger);
+    } else {
+      this.bind('DOMContentLoaded', trigger); // works for modern browsers and IE9
+      // we can not use jqLite since we are not done loading and jQuery could be loaded later.
+      JQLite(window).bind('load', trigger); // fallback to window.onload for others
+    }
   },
   toString: function() {
     var value = [];